The Solar Cycle is the increase of the minimum activity level of the Sun to the maximum activity level and back to the minimum level. It is related to the frequency, activity, and duration of sunspots. One cycle lasts about 11 years.

There are very few sunspots during periods of minimum activity, and several hundred sunspots can be observed during periods of maximum activity. At the end of each cycle, the polarity of the Sun's magnetic field reverses. It means that the north magnetic pole gives way to the south pole and vice versa.

The solar activity cycle lasts about 11 years, but there are also cycles lasting 9-14 years. Their average duration also changes over the centuries. In the 20th century, the average cycle length was 10.2 years. In the past, the beginning of the cycle was considered to be the moment when solar activity was at its minimum. Thanks to modern measurement methods, it was possible to find the change in the polarization of the Sun's magnetic field. Therefore the beginning of the cycle is considered the moment of changing the polarization of the area.

The Center for Hydrometeorology and Monitoring report that we are currently in Solar Cycle 25, which began in December 2019. According to forecasts, it will peak its activity in 2025. Compared to past cycles, this cycle is relatively calm but can change unpredictably every second.

During the periods of highest activity, the number of emissions and phenomena that can significantly affect the earth and change the space weather also increases. Among them are coronal mass ejections, intense solar flares, the increase in the number of electrons in the solar wind, and other processes characteristic of the Sun. These processes disrupt the ordinary course of the geomagnetic field and simultaneously affect the population's health.